The invention relates to a motorized roller shutter or the like comprising an electric drive motor the stator of which is connected to a fixed support via elastic means which oppose the rotation of the stator under the effect of the resistive torque exerted by the roller shutter moving between a rolled up up position and an unrolled down position, stop means stopping the roller shutter in these up and down positions and means of controlling the stopping of the motor in these up and down positions comprising a switch the opening of which is actuated by the rotation of the stator when the resistive torque exceeds the retaining force exerted by the elastic means.
Roller shutters thus equipped are described in patents FR 2 740 824, the content of which is incorporated by reference, U.S. Pat. No. 6,392,374, the content of which is incorporated by reference, and EP 0 703 344, the content of which is incorporated by reference.
The roller shutter described in patent FR 2 740 824 uses a single spring. The switch is open when the roller shutter is in the unrolled position and the motor is powered via an auxiliary switch controlled by a revolutions counter associated with the motor. Such a roller shutter has to be mounted in a determined position in a window aperture.
The roller shutters described in patents U.S. Pat. No. 6,392,374 and EP 0 703 344 are equipped with two antagonist springs between which the stator of the motor is held. One of these springs is compressed when the roller shutter, completely rolled up, arrives at a top stop, while the other spring is compressed when the roller shutter, completely unrolled, has reached the bottom stop, generally against the bottom of the aperture. Now, as described in patent FR 2 740 824, the top stop spring has to be able to oppose the torque generated by the weight of the roller shutter. Now, when the shutter is almost completely unrolled, this weight may be very great. By contrast, the spring which controls the stopping of the motor when the roller shutter reaches the bottom stop has to give relatively readily in order to avoid needless compression of the shutter reaching the bottom stop, which compression could damage the shutter. It is therefore necessary to have two springs, one of them very strong, for the top stop, and the other far weaker, for the bottom stop. Now, by equipping the stopping device with two different springs, the direction of rotation of the motor corresponding respectively to the rolling-up and to the unrolling of the roller shutter, is determined, and this means that the motor has always to be arranged on the same side of the aperture, given that if the motor is arranged on the opposite side of the aperture its direction of rotation will have to be reversed, for the same position of the roller shutter, of course, which is generally the case. This represents a constraint that cannot always be satisfied and it is therefore necessary to have two motors with their stopping control device, one for mounting on the left and the other for mounting on the right of the aperture.
The object of the invention is to produce a roller shutter the motor and the stopping device of which can be mounted with equal ease on either side of the aperture. The stopping device has also to be compact so that it can be arranged inside a motor, particularly a tubular motor, without increasing the size thereof.
The roller shutter according to the invention is characterized in that the elastic means consist of two springs working in compression between two moving compression elements driven in turn by the stator respectively in each of the directions of rotation, the distance to be covered by the driven moving element, from the rest position, before one of the springs is compressed, exceeding the distance to be covered by the driven moving element before the other spring is compressed, and in that the stopping device comprises an actuating member kinematically linked to the stator and, on the one hand, driving the compression elements and, on the other hand, actuating the switch after a determined travel which differs for each direction of rotation of the stator and means of reversing the lengths of the travels.
When the stator rotates, just one spring is compressed first of all, this compression corresponding to the shortest travel of the actuating member, that is to say to the stopping of the motor when the roller shutter reaches the bottom stop. When the moving drive element moves in the opposite direction corresponding to its long travel, just one spring is compressed first of all, then both springs are compressed, offering significantly more resistance, this situation corresponding to the roller shutter arriving at the top stop. Actuation of the means of reversing the travel lengths makes it possible to obtain the same result when the motor is rotating in the opposite direction.
The distance to be covered by the driven moving element before one of the springs is compressed may be zero.
The springs are advantageously helical, with different diameters and nested coaxially one inside the other. Such a construction is particularly compact. To simplify the construction, the compression elements advantageously have a single distance between them and the springs are of different lengths.
The spring compressed second is advantageously pre-compressed at rest. Both springs may be pre-compressed. Pre-compressing the springs makes it possible to operate on a gentle slope with short travel, which allows better control over the forces developed by the springs and therefore makes it possible to enjoy great precision in the triggering forces, particularly in that of the spring which is compressed by itself which has not to be too high in order not to damage the roller shutter. Pre-compression also makes it possible to reduce the size of the stopping device.
The actuating member may be part of the stator.
According to one embodiment, the actuating member consists of a traveler guided in the support and equipped, on one side, with two arms for driving the compression elements in the compression direction and, on the other side, with two arms for actuating the switch which is mounted between these arms and the means of reversing the length of the travels consist of a rocker mounted between the actuating arms of the switch and equipped with two arms which act alternately as arm for actuating the switch depending on the position of the rocker, the other arm being retracted relative to the switch, the active arm being situated between one of the actuating arms of the traveler and the switch.
According to an improvement of this embodiment, the arms of the rocker are flexible in a direction parallel to its axis of pivoting and the stopping device comprises a fixed stop situated in the path of the arms of the rocker, facing the open position of the switch, this stop having the effect of moving the active actuating arm of the rocker away from its normal active path so as to make it inoperative. This improvement prevents the motor from being powered in the rolling-up direction if an attempt is made at raising the roller shutter by hand, for example in the event of an attempted break-in.
According to another embodiment, the switch is mounted between the arms of the traveler and can move in the same direction as the traveler, so as to be able to alter the distance separating it from each of the actuating arms of the traveler, that is to say the length of the travel needed to actuate it using the traveler in each of the directions of rotation of the stator.
According to one embodiment, the springs are mounted in a cage one of the ends of which has a lateral arm driven directly by the traveler, the compression element compressing the other ends of the springs consisting of a part in the form of a piston entering the cage and the strongest spring which is pre-compressed between the two ends of the cage.